[mythtv] MythGame screenshots

[Greg Estabrooks]

> The code in RomInfo::FindImage() in rominfo.cpp aborts the lookup if
> there's no '.' in the filename.  Instead, it should append a '.' to the

 This is fixed now.

> Also, it should be possible to use subdirectories under the screenshots

 I disagree here. I don't think it's worth the incurred overheard of checking
the subdirectories as well as the base screenshot directory(which
is a behaviour I wont get rid of). Currently it checks for 12 possible image
types, and if I allowed it to look in more than one location that would be 12
checks in each directory.